Transcript COST 531 closing meeting 2007 (Vienna)

Jiri Vizdal1 and Ales Kroupa2
1Department
of Inorganic Chemistry / Materials Chemistry
Faculty of Chemistry
University of Vienna
Vienna, Austria
2Structure
of Phases Group
Department of Structure
Institute of Physics of Materials, AS CR
Brno, Czech Republic
in Lead-free solders
Phase Equilibria
Bi-Sn-Zn & Pd-Sn-Zn Systems:
Summary of the Results
Presentation outline
 Aims + used methodology
 Experimental methods summary
 Results…
• Bi-Sn, Bi-Zn, Bi-Sn-Zn
• Pd-Zn, Pd-Sn-Zn
 Conclusions
Aims & methodology

Our work was aimed at thermodynamic and experimental
description of phase equilibria in the Bi-Sn-Zn, Pd-Sn-Zn (Pd –
Pd/Ni substrate coatings) systems and relevant subsystems >>>
• contribution to new Pb-free solders design

Analysis + literature survey:
• optimal thermodynamic assessments selection (if exist!)
• 1. version of the thermodynamic database

Theoretical study („CALPHAD“ -> Thermo-Calc):
• predictions calculations

Experimental study (SEM + EDS/WDS, DTA/DSC, etc.)

Theoretical study:
• modelling -> „COST531“ thermodynamic database expansion
Our goals and how to achieve them...
Experimental details
Materials, treatment
 Bi, Sn, Zn, Pd ≥ 99,95 %
 Samples were sealed under vacuum
into quartz capsules.
 Homogeneity {SEM (BSE) + EDS}.
 Heat treatment – annealing
(different T, t).
 Coolant: H2O.
 Phase identification and
composition measurement. >>>
 Phase transformations
temperatures measurement. >>>
Exp. methods
 SEM + EDS/WDS (JEOL JSM-6460;
BSE; 20 keV / INCA + standards + ZAF)
 TEM + EDS
(TEM/STEM Philips CM
12 / EDAX Phoenix CM 12)
 DTA/DSC (Netzsch DTA/DSC 404;
Dept. of Inorganic Chemistry /
Materials Chemistry, University of
Vienna):
•
•
•
•
standards: Au/Ag
vheating/cooling ~ 2 °C/min.
accuracy: ±2 °C
atmosphere: vacuum/Ar
Exp. methods summary
Experimental & Theoretical
Results
Bi-Sn: optimization results
Calculated activity
of Sn in Liq. in
comparison to exp.
data from Asryan &
Mikula [ASR 2004]
TE ~ 138.4 °C
Enthalpy of mixing
in comparison to
experimental data
from [ASR 2004] and
[SHARKEY 1972]
[COST 2006]
Newly modified Bi-Sn system description,
that was originally published by [OHT 1994]
Bi-Sn: Final assessment
Bi-Zn: assessment correction
SEM/WDS
Liq.
Overall compos.
Bi-76.2Zn
Bi in HCP_Zn (Zn)
0.3  0.2
Zn in (Bi)
0.3  0.1
Liq. + (Zn)
(Bi) + (Zn)
Values in wt. %
Malakhov [MAL 2000]
0 ( Zn )
Bi ,Zn:Va
L
After change
Malakhov [MAL 2000]: 35 000 J/mol
Optimization:
25 000 J/mol
Annealed 864 h/200 °C
Bi-Zn: Final assessment
Bi-Sn-Zn: selected isopleths
Bi/Zn = 1/2
D
C
[This work]
(Bi)
+ (Sn)
+ (Zn)
A
E
T1 +
+ T2
A
w(Sn) = 59 hm. %
B
Liq. + (Zn)
Liq. + (Zn)
(Bi) + (Sn) + (Zn)
(Sn)
+
(Zn)
[BRA 2007]
T = 120 °C
Liq. + (Sn) + (Zn)
(Bi) + (Sn) + (Zn)
B
[COST 2006]
(Bi) + (Zn)
Liq. + (Zn)
(Bi) + (Sn) + (Zn)
[LUEF 2006]
(Sn) + (Zn)
[BRA 2007]
Isothermal section (120 °C)
together with selected
vertical sections
compared to available
experimental data…
At.
%
x(Zn) = 5 at. %
w(Zn) = 12 hm. %
Liq. + (Sn)
+ (Zn)
Liq. + (Bi)
+ (Zn)
(Bi) + (Sn) + (Zn)
Bi-Sn-Zn: New assessment
Bi-Sn-Zn: therm. properties
1
2
3
4
Activities in comparison to
exp. data from [OLE 1959]
Enthalpies of mixing
compared to exp.
data from [LUEF 2006]
[COST 2006]
Bi-Sn-Zn: New assessment
Pd-Zn: overview
Massalski’s experimental phase diagram [MASS 1990]
Phase diagram by Hansen and Anderko [HAN 1958]
?
?
• Thermodynamic activities of Zn in ordered β1 Pd-Zn alloys at 1000 °C were
measured by Kou and Chang [KOU 1975].
• Partial molar and integral properties were determined from vapour pressure
measurements by Chiang [CHI 1977] (477 – 1030 °C / 0 – 83 at. % Zn).
[E-MRS 2005]
Pd-Zn: The reason of study
Pd-Zn: phase diagram
Pd-Zn phase diagram, calculated on the basis of
newly optimized thermodynamic parameters
in comparison with available exp. data.
[E-MRS 2005]
The detail of the phase diagram showing
new exp. information – marked invariant
reactions (DTA) and phase‘s composition
(SEM + EDS).
Pd-Zn: New assessment
Pd-Zn: therm. properties
Comparison of exp. measured [CHI 1977] and calculated values of:
1. Zn activities in (Pd);
2. integral molar Gibbs energy for the Pd-Zn system
at 1000 °C in different concentration ranges.
[E-MRS 2005]
Pd-Zn: New assessment
Pd-Sn-Zn: prediction + exp.
500 °C
900 °C
Calculated isothermal sections in the Pd-Sn-Zn system at 500 and 900 °C
based only on binary data together with marked exp. alloys.
Binary prediction + proposed exp. alloys
Pd-Sn-Zn: SEM/TEM + EDS
500 °C
900 °C
Preliminary experimental phase diagrams design – isothermal sections constructed
according to SEM/TEM + EDS marked experimental results.
Experimental phase diagram
Conclusions
Conclusions…
 Bi-Sn-Zn system and relevant subsystems:
•
Exp. determined max. solubility of Bi in (Sn) at TE ~ 10 wt. % -> created new
assessment of the Bi-Sn system.
•
Exp. determined solubilities of Bi in (Zn) and Zn in (Bi) at T = 200 °C -> correction of
the present Bi-Zn assessment.
•
Exp. study of the Bi-Sn-Zn system (SEM + EDS/WDS, DTA) -> own results + results from
literature were used for the new assessment (interact. param. for Liq. and (Bi)).
 Pd-Zn and Pd-Sn-Zn systems:
•
Exp. study of Zn-rich part of the Pd-Zn phase diagram verified presence of the η-phase
at T = 400 °C.
•
Eutectic reaction was established in this part of the Pd-Zn diagram: Liq.  η + (Zn).
•
First thermodynamic description of the Pd-Zn system has been created.
•
First predictions within the Pd-Sn-Zn system were calculated and relevant exp. results
at 500 a 900 °C were obtained. These were used for the preliminary exp. phase
diagram construction.
 Presented finished thermodyn. descriptions of the Bi-Sn, Bi-Zn, Pd-Zn and
Bi-Sn-Zn systems are in very good agreement with available data and sets
of thermodynamic parameters were included in the „COST531“ database.
Acknowledgements
• COST No. OC 531.002 (Ministry of Education of the Czech Republic)
• No. 106/05/H008 (Czech Science Foundation)
• AV0Z20410507 (Research project)
Cooperation:
• Dr. Milan Svoboda (IPM AS CR)
• Prof. Klaus W. Richter (University of Vienna)
• Dr. Christoph Luef (University of Vienna)
• Prof. Aloke Paul (Indian Institute of Science)
• Prof. M. H. Braga (Universidade do Porto)
• Prof. L. F. Malheiros (Universidade do Porto)
• Prof. D. Soares (Universidade do Minho)
<<< Publications
This work was supported by following projects:
Literature
[COST 2006]
Vizdal, J., Braga, M.H., Kroupa, A., Malheiros, L.F., Soares, D.:
In COST 531 Mid-Term Meeting, Genoa, Italy, 2006.
[ASR 2004]
Asryan, N., Mikula, A.: Z. Metallkd. 95 (2004).
[SHARKEY 1972]
Sharkey, R.L., Pool, M.J.: Met. Trans. 3 (1972).
[OHT 1994]
Ohtani, H., Ishida, K.: J. of El. Mat. 23 (1994).
[OEL 1958]
Oelsen, W., Golücke, K.F.: Arch. Eisenhüttenw. 29 (1958).
[NAG 1952]
Nagasaki, S., Fujita, E.: J. Jpn. Inst. Met. 16 (1952).
[MAL 2000]
Malakhov, D.V.: Calphad 24 (2000).
[BRA 2007]
Braga, M.H., Vizdal, J., Kroupa, A., Ferreira, J., Soares, D., Malheiros, L.F.:
Calphad, accepted for publication, 2007.
[LUEF 2006]
Luef, Ch., Paul, A., Vizdal, J., Kroupa, A., Kodentsov, A., Ipser, H.:
Monatsh. Chem. 137 (2006).
[OLE 1959]
Oleari, L., Fiorani, M.: L. Ricerca Scientifica 29 (1959).
[E-MRS 2005]
Vizdal, J., Kroupa, A., Popovic, J., Zemanova, A.: In E-MRS int. Fall Meeting,
p. 177, ISBN 83-89585-07-3, Warsaw, Poland, 2007.
[MASS 1990]
Massalski, T.B.: Binary Alloy Phase Diagrams, ASM Int., Ohio, USA 1990.
[HAN 1958]
Hansen, M., Anderko, K.: Constitution of Binary Alloys, New York, 1958.
[KOU 1975]
Kou, S., Chang, Y.A.: Acta Metall. 23 (1975).
[CHI 1977]
Chiang, T., et al.: Z. Metallkd. 68 (1977).